sandbox: Extend BrokerPolicy to support file creation

content/common/sandbox_linux/bpf_cros_arm_gpu_policy_linux.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/sandbox_linux/bpf_cros_arm_gpu_policy_linux.h"
 
 #include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
 #include "content/common/sandbox_linux/sandbox_bpf_base_policy_linux.h"
 #include "content/common/sandbox_linux/sandbox_seccomp_bpf_linux.h"
 #include "sandbox/linux/bpf_dsl/bpf_dsl.h"
 #include "sandbox/linux/seccomp-bpf-helpers/syscall_sets.h"
 #include "sandbox/linux/services/linux_syscalls.h"
+#include "sandbox/linux/syscall_broker/broker_process.h"
 
-using sandbox::SyscallSets;
 using sandbox::bpf_dsl::Allow;
 using sandbox::bpf_dsl::Arg;
 using sandbox::bpf_dsl::Error;
 using sandbox::bpf_dsl::If;
 using sandbox::bpf_dsl::ResultExpr;
+using sandbox::syscall_broker::BrokerFilePermission;

[Jorge Lucangeli Obes, 2014/11/20 00:13:20]

Should we change this to be simply "FilePermission" since it lives in the
syscall_broker namespace? I think Matthew had suggested it.

[leecam, 2014/11/20 00:56:38]

As discussed as everything else in the syscall_broker namespace still is
prefixed with Broker it kinda looks out of place. Will leave for now and maybe
we could land a CL that reworks the naming later.

+using sandbox::SyscallSets;
 
 namespace content {
 
 namespace {
 
 inline bool IsChromeOS() {
 #if defined(OS_CHROMEOS)
   return true;
 #else
   return false;
 #endif
 }
 
 inline bool IsArchitectureArm() {
 #if defined(__arm__)
   return true;
 #else
   return false;
 #endif
 }
 
-void AddArmMaliGpuWhitelist(std::vector<std::string>* read_whitelist,
-                            std::vector<std::string>* write_whitelist) {
+void AddArmMaliGpuWhitelist(std::vector<BrokerFilePermission>* permissions) {
   // Device file needed by the ARM GPU userspace.
   static const char kMali0Path[] = "/dev/mali0";
 
   // Devices needed for video decode acceleration on ARM.
   static const char kDevMfcDecPath[] = "/dev/mfc-dec";
   static const char kDevGsc1Path[] = "/dev/gsc1";
 
   // Devices needed for video encode acceleration on ARM.
   static const char kDevMfcEncPath[] = "/dev/mfc-enc";
 
-  read_whitelist->push_back(kMali0Path);
-  read_whitelist->push_back(kDevMfcDecPath);
-  read_whitelist->push_back(kDevGsc1Path);
-  read_whitelist->push_back(kDevMfcEncPath);
-
-  write_whitelist->push_back(kMali0Path);
-  write_whitelist->push_back(kDevMfcDecPath);
-  write_whitelist->push_back(kDevGsc1Path);
-  write_whitelist->push_back(kDevMfcEncPath);
+  permissions->push_back(BrokerFilePermission::ReadWrite(kMali0Path));
+  permissions->push_back(BrokerFilePermission::ReadWrite(kDevMfcDecPath));
+  permissions->push_back(BrokerFilePermission::ReadWrite(kDevGsc1Path));
+  permissions->push_back(BrokerFilePermission::ReadWrite(kDevMfcEncPath));
 }
 
-void AddArmGpuWhitelist(std::vector<std::string>* read_whitelist,
-                        std::vector<std::string>* write_whitelist) {
+void AddArmGpuWhitelist(std::vector<BrokerFilePermission>* permissions) {
   // On ARM we're enabling the sandbox before the X connection is made,
   // so we need to allow access to |.Xauthority|.
   static const char kXAuthorityPath[] = "/home/chronos/.Xauthority";
   static const char kLdSoCache[] = "/etc/ld.so.cache";
 
   // Files needed by the ARM GPU userspace.
   static const char kLibGlesPath[] = "/usr/lib/libGLESv2.so.2";
   static const char kLibEglPath[] = "/usr/lib/libEGL.so.1";
 
-  read_whitelist->push_back(kXAuthorityPath);
-  read_whitelist->push_back(kLdSoCache);
-  read_whitelist->push_back(kLibGlesPath);
-  read_whitelist->push_back(kLibEglPath);
+  permissions->push_back(BrokerFilePermission::ReadOnly(kXAuthorityPath));
+  permissions->push_back(BrokerFilePermission::ReadOnly(kLdSoCache));
+  permissions->push_back(BrokerFilePermission::ReadOnly(kLibGlesPath));
+  permissions->push_back(BrokerFilePermission::ReadOnly(kLibEglPath));
 
-  AddArmMaliGpuWhitelist(read_whitelist, write_whitelist);
+  AddArmMaliGpuWhitelist(permissions);
 }
 
 class CrosArmGpuBrokerProcessPolicy : public CrosArmGpuProcessPolicy {
  public:
   static sandbox::bpf_dsl::Policy* Create() {
     return new CrosArmGpuBrokerProcessPolicy();
   }
   ~CrosArmGpuBrokerProcessPolicy() override {}
 
   ResultExpr EvaluateSyscall(int system_call_number) const override;
@@ skipping 50 matching lines @@
       // Default to the generic GPU policy.
       return GpuProcessPolicy::EvaluateSyscall(sysno);
   }
 }
 
 bool CrosArmGpuProcessPolicy::PreSandboxHook() {
   DCHECK(IsChromeOS() && IsArchitectureArm());
   // Create a new broker process.
   DCHECK(!broker_process());
 
-  std::vector<std::string> read_whitelist_extra;
-  std::vector<std::string> write_whitelist_extra;
   // Add ARM-specific files to whitelist in the broker.
+  std::vector<BrokerFilePermission> permissions;
 
-  AddArmGpuWhitelist(&read_whitelist_extra, &write_whitelist_extra);
-  InitGpuBrokerProcess(CrosArmGpuBrokerProcessPolicy::Create,
-                       read_whitelist_extra,
-                       write_whitelist_extra);
+  AddArmGpuWhitelist(&permissions);
+
+  InitGpuBrokerProcess(CrosArmGpuBrokerProcessPolicy::Create, permissions);
 
   const int dlopen_flag = RTLD_NOW | RTLD_GLOBAL | RTLD_NODELETE;
 
   // Preload the Mali library.
   dlopen("/usr/lib/libmali.so", dlopen_flag);
   // Preload the Tegra V4L2 (video decode acceleration) library.
   dlopen("/usr/lib/libtegrav4l2.so", dlopen_flag);
   // Resetting errno since platform-specific libraries will fail on other
   // platforms.
   errno = 0;
 
   return true;
 }
 
 }  // namespace content